As I was dissussing on the server yesterday, we really need to either randomize the map rotation, or change the order frequently. Many people are only able to play at certian times, meaning that they play the same maps each time they are able to join. In my own case, each time I join the server for casual play we go through the same rotation: cp_yukon, pl_waste, cp_furnace, then ctf_aurora; after which I need to leave. I still have yet to play pl_cashworks on a server that isn't filled with only 3 people.
Also, I support adding more custom maps to the rotation. While I'm hesitent to suggest mixing arena with normal maps, I think koth versions would fit nicely.
Although I do support arena_offblast once the "classless" update is released, mostly to honour the mapper for having his map made official.